There are two major types of automotive doors with extendable glass. In one type of automotive door, the glass is supported above a belt line of the automotive door. This type of door is mainly utilized in full-size vehicles, especially large luxury vehicles. The second type of automotive door is referred to as a hard-top door. In the hard-top door, the glass is unsupported above the belt line of the automotive door. The hard-top door is popular in sports-type vehicles or in convertibles.
An excellent example of an automotive hard-top door is shown in commonly-assigned U.S. Pat. No. 5,340,976 to Wirsing. In the hard-top door, all support of the door is below the belt line. Before the present invention, a compromise between two factors typically had to be made. Typically, the glass is laterally supported on the outboard side of the door by the seal which seals the window glass to prevent water from entering the cabin of the door. On the inboard side, the glass is typically supported by what is commonly referred to as a stabilizer. Window glass being a rigid ceramic is an ideal amplifier for any vibrational noises. Therefore, to minimize vibrational noise, the glass is allowed a fair amount of play to prevent the generation of squeal noise when the window is moved up or down. This is especially critical when the glass is wet. However, the play in the lateral support of the glass presents another problem of rattle when shutting the door when the glass is not fully retracted or extended upward. Although this rattling noise has little or no effect on the operational characteristics of the vehicle window system, it does sometimes generate customer dissatisfaction. Accordingly, a battle rages between these two conflicting desires--the elimination of squeal noise in the operation of the window, especially when the glass is wet, versus a rattling noise which is generated when the window door is shut, generating lateral forces in the window glass up to and approaching 65 pounds.